Photo Insight with Heather Angel

Heather Angel explains how she used fill flash to photograph this scurrying harvest mouse on a seed head

An internationally renowned photographer of the natural world and author of more than 50 books, Heather brings her expertise to AP.

I photographed this harvest mouse at the British Wildlife Centre in Lingfield, Surrey (www.britishwildlifecentre.co.uk). I love it there and often visit to photograph its variety of mammals and birds. On this occasion the warden had brought out the mouse and placed it on a seed head that was in a pot of sand. The mouse was free to run up and down the stem and not contained in any way. It moved incredibly quickly, and the warden had to keep catching it to make sure it didn?t scurry away!

The harvest mouse is the smallest British rodent. It is just 55-75mm long and weighs 4-11 grams, which is half the weight of a house mouse.

I used a 105mm macro lens with my Nikon D3 for this shot because the mouse was tiny. The green, natural-looking background is nicely thrown out of focus by the macro lens. I chose a background that was uncluttered to make sure it did not detract from the subject.

When you?re photographing this close, every detail is magnified so you have to make sure your focusing is spot on. I wanted to ensure that the head of the mouse, and in particular its eye, was in focus.

I used autofocus because manual focus would have been too slow, and I switched my AF points as the mouse moved. If you keep your focus set to the central AF point, you may find the eyes will be out of focus as the subject moves. Moving the AF points in line with where the subject moves gives you a better chance of getting the eyes in focus. You can see that I have moved the AF point because the eyes are in focus in both images, even though the mouse is in a different position. Moving the AF point as the subject moves takes practice to get right, but it does become easier the more you do it.

It was late in the day and the light was a little overcast, so I used fill flash balanced with natural daylight to illuminate this image. I wanted a subtle effect so I made sure the flash power wasn?t too high. If the flash had been too powerful, it would have turned the background black and made the scene look like night-time ? something I didn?t want to happen.

To ensure that the image looked natural and to avoid burning out areas of the subject, I exposed for the background and set my SB-800 flash gun to -1.7 EV. The flash was attached to my camera ? it would have been impossible to hold the flash because the mouse was moving so fast. If you look closely you can see the catchlight caused by the flash in the mouse?s eye. It just adds a little sparkle to the image and brings out detail in the fur.

I think some photographers avoid flash because they are unsure how to use it effectively. This is one of the key techniques I teach at my workshops. Essentially, you meter for the ambient exposure and adjust the flash power accordingly. I find setting the flash to -1.7EV is a good starting point for an average scene like this, but for a lighter coloured subject you might need to reduce the flash output.

The exposure was 1/320sec at f/10. Normally, if you set a faster shutter speed than the camera?s recommended flash sync speed, you will see a black strip in your image where the camera has been unable to synchronise the shutter to the flash. Fortunately, I was able to use my Nikon camera?s Creative Lighting system, which allowed me to set a flash sync speed that was faster than 1/250sec.

It?s very difficult to ?compose? an image like this because the mouse doesn?t stay still for long enough. Consequently, there is an element of luck involved and you may find you have to take lots of shots until you have one you are happy with. Keep assessing your shots and analysing the position of the subject in the frame so you can work out the best possible place.

These images work wonderfully as a pair ? the top picture was taken just before the one above, when the mouse scampered down the stem. You don?t always get the best shots straight away, so you have to keep ?working? the composition and trying different framings.

Heather Angel was talking to Gemma Padley

To see more images by Heather visit www.heatherangel.co.uk or www.naturalvisions.co.uk. Heather regularly runs workshops at the British Wildlife Centre. For information on courses run by Heather and her son Giles, visit www.photographyandphotoshopcourses.co.uk